A big note, if you plan to use high jump, be very warned, jumping into choppers and stuff in some missions and other things, and jumping ahead of where the game is scripted to do special things can make it impossible to complete a mission.

after this stage (if i can manage to jump into the pave low) then i should get a trophy and be able to confirm.

EDIT: okay, just jumped into the pave low, it has nothing to do with hitting the target, just jumping forward from the very edge of the roof.